Applicant's U.S. Pat. No. 3,969,845 dated July 20, 1976 directed to a door construction disclosed a door hinged to a frame having a locking channel pivotally mounted upon a vertical axis upon its closing edge and interlocked with an elongated engaging element upon the frame wherein the channel was sufficiently movable relative to the door that it disengaged the locking element so that the door may open.
A blocking means was movably mounted upon the door, in one position retaining the channel in a locked position when the door was closed and movable to a channel release position. Said patent further disclosed a manually releasable blocking means upon the door for preventing pivotal movement of the channel with respect to the door.
Applicant's improvement U.S. Pat. No. 4,093,284 dated June 6, 1978 was further directed to a door construction wherein additionally there was disclosed a pivotal actuator within the door in operative engagement with a channel blocking member together with push pull type of control assembly mounted upon the door and operatively engageable with the actuator for moving the actuator, and in turn the channel blocking means from a locked position to a release position.